Fat tissue stores energy, provides insulation and defines exterior structural features, for example in the face, breasts, buttocks or any other form-defining body parts of mammals. Next to cosmetic desires there are also therapeutic applications for fat tissue engineering and reconstruction, e.g. breast reconstruction after mastectomies, HIV-induced lipid dystrophy and facial reconstruction after trauma.
Traditional methods for treating fat tissue defects and for cosmetic tissue augmentation employ a filling material that replaces or adds volume to the targeted body part. The filling materials are classified as autologous fillers and non-autologous fillers.
Autologous fat transfer, i.e. surgical fat cell isolation from one part and re-injection into another part of the body, has been practiced since the late 19th century. Autologous fat cell transfer to the face has the advantage of its permanent nature and the autologous fat based injections result in a more soft and glowing look of the rejuvenated face. On the other hand, a major drawback is the unpredictability of the results due mostly to varying survival rates of adipose cells after injection. For example, for fat cells injected into fat tissue areas (e.g. face or breasts) 30-70% die, mainly because of the absence of nutrients and oxygen in the pre-angiogenic state. Another problem is the survival of the fat cells during isolation. This issue has been improved by a number of techniques such as the use of aspirated needles and specialized treatment of the isolated fat cells. A further drawback of this technique is that it requires surgical intervention and adequate amounts of autologous fat cell materials, which is not available for many individuals.
A more modern course of action in fat tissue engineering is the injection of adipose derived stem cells (ADSC) that cause proliferation of new adipocytes. However, the process involves a lengthy, complicated and expensive procedure including liposuction, isolation of ADSC from the adipose cells by specialized ultracentrifugation, optionally with the treatment of the isolated ADSCs with differentiating factors, and reinjection of differentiated cells into the desired target tissue.
Because of the cell survival issue of fat cells various non-cellular filler materials were envisaged. Collagen was the most widely used filler in the market till the emergence of hyaluronic acid in 2003. Collagen induces mild immunogenic reactions because of its bovine source and this technology came to an end with the emerging awareness of the risk of bovine spongiform encephalopathy (BSE). Hyaluronic acid (HA) has been used as an off prescription fat tissue filler for years even though it was FDA approved much later in 2003. It has become the most dominant filler on the market. Modern commercial HA is highly crosslinked with divinyl sulfone-based compounds for increased half-life and of recombinant rather than animal source for reducing immunity. The principle drawback of HA is its limited life span after injection. Most HA-based fillers endure for 3 to 12 months only. As with silicon-based implants, the use of HA for breast enhancement can interfere with mammography-based cancer detection. Other potential issues related to HA are a higher frequency and risk of granuloma development, nodule formation and mastalgia, implant palpability, capsular contraction, superficial infections and abscess development.
Local and systemic administration of estrogens has also been known to increase women's breast size by estradiol receptor induction of adipose tissue generation. Spironolactone has been known to induce breast development and feminization due to its anti-androgen properties.
Another approach for the de-novo adipose tissue generation is the long-term local delivery of insulin and insulin-like growth factor-1 (IGF-1) and basic fibroblast growth factor (bFGF) by PLGA/PEG microspheres and this has been tested in an in vivo rat model (Yuksel et al., Plastic & Reconstructive surgery, vol. 105(5), April 2000, 1712-1720), wherein insulin- and IGF-1-containing microspheres were administered directly to the deep muscular fascia of the rat abdominal wall to evaluate their potential for the de novo adipose tissue generation via adipogenic differentiation from non-adipocyte cell pools. The microspheres function as controlled release (CR) compounds that provide for a long-term local delivery of the proteins that induce the de novo generation of adipose tissue at the administration site.
In summary, the prior art techniques for treating fat tissue defects and for cosmetic fat tissue augmentation require either the autologous transfer of fat cells or adipose derived stem cells (ADSC), the local administration of non-cellular non-permantent fillers or, alternatively, the local administration of adipocyte differentiation and growth factors.
It is the objective of the present invention to provide a composition for treating fat tissue defects and for cosmetic fat tissue augmentation that is technically easy to produce and administer, that requires minimal surgical intervention and that is safe and cost efficient.
In a first aspect the problem underlying the present invention is solved by the provision of a composition comprising (i) physiologically acceptable, metabolic lipids, and (ii) physiologically acceptable, preferably biodegradable controlled release (CR) compounds, wherein the metabolic lipids are cell-free and the CR compounds release the metabolic lipids over a delayed time period under physiological conditions.
The term controlled release (CR), as used herein, refers to the technology of formulating active compounds to control the active compounds availability, e.g. a timed release such as for example a sustained (prolonged) release, a pulse release, a delayed release, etc. and combinations thereof. Typical CR applications are fertilizers, cosmetics and pharmaceuticals. CR compounds for use in the present invention are compounds formulated together with said lipids and optionally other physiologically active compounds that delay the release of said lipids and active compounds in comparison to the absence of the CR compounds when administered to a physiological environment, preferably a human body tissue part such as of the face, breasts, buttocks, etc.
The CR compounds and metabolic lipids for use in the invention should be physiologically acceptable, i.e. substantially non-toxic to the treated tissue. It is further preferred that the CR compounds of the invention are substantially biodegradable, i.e. they are removed and preferably metabolized from the administration site with time.
The CR compounds release the metabolic lipids and optionally other active compounds over a delayed time period under physiological conditions. Physiological conditions, as mentioned herein in the context of the invention, are the in vivo conditions at the tissue site of administration, e.g. adipose tissue conditions.
The release profile of the CR compounds for the metabolic lipids and optionally other active compounds is not limited and depends on the formulation of the composition as well as on the target tissue and the mode and frequency of administration. Generally, an initial burst release followed by a steady state release initiate adipocyte growth and/or proliferation while maintaining a physiologically effective level of the metabolic lipids and the optional active compounds desired.
In a preferred embodiment the CR compounds release the metabolic lipids and optionally other active compounds over a delayed time period of 7 days to 12 months, preferably 30 to 90 days, more preferably 50 to 70 days, most preferably over about 60 days.
The metabolic lipids for use in the composition of the invention are cell-free, meaning that they do not form part of living or dead cells and that they are essentially free of cellular components such as membranes, nuclei, nucleic acids, etc. Cell-free metabolic lipids have the advantage that they are less immunogenic, pharmacologically safe and more accessible to absorption by cells such as the cells in the target tissue.
Lipophilicity refers to the ability of a chemical compound to dissolve in fats, oils, lipids and non-polar solvents such as hexane or toluene. The term metabolic lipids as used herein is defined as any compounds that are lipophilic and that can be ingested, stored and metabolized for producing cellular energy, e.g. ATP, by cells, preferably by cells in adipose tissues, more preferably by adipocytes.
The composition of the invention can be locally administered, e.g. by injection, preferably multiple and evenly distributed injections, into tissues for treating fat tissue defects and for cosmetic fat tissue augmentation.
The released metabolic lipids have a number of advantageous effects on the treated tissue. Contrary to isolated cells, e.g. fat cells and ADSC, metabolic lipids are less immunogenic, they do not comprise harmful constituents such as bovine-derived collagen (BSE) and they can be ingested by target cells directly and fast. The direct and advantageous effect of the inventive composition on fat cells and other cells in the target tissue is that these cells are continuously “superfed” leading to increased volume.
To further assist the growth of the target tissue the composition of the invention can comprise further active compounds, preferably fat cell growth effector compounds which will increase fat cells in size and numbers, i.e. stimulate fat cell growth and adipogenesis, i.e. cell differentiation of pre-adipocytes into adipocytes and adipocyte volume growth.
In a more preferred embodiment the composition of the present invention comprises at least one fat cell growth effector, preferably a fat cell growth effector selected from the group consisting of    a. insulin, insulin growth factor binding proteins 1 to 7 (IGFBP 1-7), insulin growth factor 1 (IGF-1) and insulin growth factor 2 (IGF-2), preferably insulin, insulin-growth factor 1 (IGF-1) and insulin growth factor 2 (IFG-2), more preferably insulin and insulin-growth factor 1 (IGF-1), most preferably human insulin;    b. fibroblast growth factors (FGFs), preferably FGF-1, FGF-2, FGF-10 and FGF-21, more preferably FGF-1 and FGF-2, most preferably FGF-1;    c. glucocorticoids, preferably selected from the group consisting of cortisol, cortisone, prednisone, prednisolone, triamcinolone, methylprednisolone, dexamethasone and betamethasone, preferably dexamethasone and betamethasone;    d. cyclic adenosine monophosphate (cAMP) activators, preferably selected from the group consisting of aminophylline, pentoxyfilline, theophylline, isobutyl-methylxanthine (IBMX), forskolin and dehydroabietic acid (DAA), preferably aminophylline, pentoxyfilline and theophylline;    e. peroxisome proliferator-activated receptor γ-2 (PPARγ2) agonists, preferably thiazolidinedione class compounds, more prefereably selected from the group consisting of pioglitazone, troglitazone, rosiglitazone and indomethacin, preferably troglitazone and rosiglitazone;    f. bone morphogenetic proteins (BMPs), preferably BMP-2, BMP-4, BMP-7 and BMP-9, preferably BMP-2 and BMP-4.
Some target tissues comprise glandular tissue or are located adjacent to glandular tissue, in particular in the female breasts. It is preferred that the glandular tissue adjacent to or surrounding the target tissue grows together with the adipose tissue so that the result as a whole is more even, natural and aestetically pleasing.
In a more preferred embodiment the composition of the invention is one specifically formulated for the growth of breast target tissue, further comprising at least one glandular growth effector, preferably a mammary glandular growth effector, more preferably a glandular growth factor selected from the group consisting of    a. estradiol and estradiol derivatives, preferably selected from the group consisting of estradiol benzoate, estradiol hemihydrate, estradiol acetate, estradiol cypionate, estradiol valerate, ethinyl estradiol and 17β-estradiol, more preferably estradiol and estradiol cypionate, most preferably 17β-estradiol;    b. epidermal growth factor (EGF), vascular endothelial growth factor (VEGF)-A, vascular endothelial growth factor (VEGF)-C, transforming growth factor-α (TGF-α), epiregulin (EPR), epigen, betacellulin (BTC), all neuregulin-1 (NRG1) isoforms, Heregulin (HRG), acetylcholine receptor-inducing activity (ARIA) growth factor, glial growth factor (GGF)), neuregulin-2 (NRG2), neuregulin-3 (NRG3), neuregulin-4 (NRG4), heparin-binding EGF-like growth factor (HB-EGF) and amphiregulin (AR), preferably epidermal growth factor (EGF), transforming growth factor-α (TGF-α), neuregulin-4 (NRG4), heparin-binding EGF-like growth factor (HB-EGF) and amphiregulin (AR), more preferably human epidermal growth factor (EGF);    c. anti-androgens, preferably selected from the group consisting of bicalutamide, nilutamide, spironolactone and flutamide, more preferably spironolactone and flutamide.
In a further preferred embodiment the metabolic lipids for use in the invention comprise fatty acids, preferably fatty acids selected from the group consisting of butanoic acid and longer chain fatty acids, more preferably selected from the group consisting of pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, eicosanoic acid, heneicosanoic acid, docosanoic acid, tricosanoic acid, pentacosanoic acid, hexacosanoic acid, heptacosanoic acid, octacosanoic acid, nonacosanoic acid, triacontanoic acid, henatriacontanoic acid, dotriacontanoic acid, tritriacontanoic acid, tetratriacontanoic acid, pentatriacontanoic acid, hexatriacontanoic acid, myristoleic acid, palmitoleic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, linolenic acid, preferably a-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, docosahexanoic acid, stearidonic acid, docosapentaenoic acid, eicosatetraenoic acid and docosahexaenoic acid, more preferably fatty acids selected from the group consisting of octadecanoic acid, dodecanoic acid, hexadecanoic acid and oleic acid, most preferably hexadecanoic acid, octadecanoic acid, and oleic acid.
In a further preferred embodiment the physiologically acceptable, preferably biodegradable CR compounds for use in the invention are selected from the group consisting of poly(lactic-co-glycolic acid) (PLGA), polylactic acid (PLA), polycaprolactone (PCL), poloxamers, polyethylene glycol (PEG)-PLGA co-polymers, combinations of PEG and PLGA, combinations of PLA and PEG, preferably PLA-PEG-PLA, combinations of PLGA and poloxamers, dextran, alginate and polymethacrylate, preferably PLA, PLGA and PEG-PLGA combinations, more preferably PLGA and PLA, most preferably PLGA.
In the following, most preferred but non-limiting embodiments of the compositions of the invention are described.
In a most preferred embodiment the present invention teaches a composition, preferably without fat cell growth effectors or glandular growth effectors, comprising biodegradable poly(lactic-co-glycolic acid) (PLGA) microspheres, hexadecanoic acid and/or oleic acid and optionally vitamin C and/or E, preferably comprising    (i) PLGA with a molecular weight of 21,000 Da and a ratio of lactic acid and glycolic acid of about 1:1,    (ii) hexadecanoic acid and/or oleic acid, preferably associated with albumin and    (iii) vitamin C and/or E.
In a further most preferred embodiment the present invention teaches a composition with at least one fat cell growth effector, comprising biodegradable poly(lactic-co-glycolic acid) (PLGA) microspheres, hexadecanoic acid and/or oleic acid, insulin, FGF-1, rosiglitazone, betamethazone and optionally vitamin C and/or E, preferably comprising    (i) PLGA with a molecular weight of 21,000 Da and a ratio of lactic acid and glycolic acid of about 1:1,    (ii) oleic acid and/or hexadecanoic acid, preferably associated with albumin,    (iii) human recombinant insulin, FGF-1, rosiglitazone, betamethasone and vitamin C and/or E.
In a further most preferred embodiment the present invention teaches a composition, preferably for breast treatment, with at least one fat cell growth effector and at least one glandular growth factor, comprising biodegradable poly(lactic-co-glycolic acid) (PLGA) microspheres, hexadecanoic acid and/or oleic acid, insulin, FGF-1, rosiglitazone, betamethazone, EGF-1, spironolactone, estradiol and optionally vitamin C and/or E, preferably comprising    (i) PLGA with a molecular weight of 21,000 Da and a ratio of lactic acid and glycolic acid of about 1:1,    (ii) hexadecanoic and/or oleic acid, preferably associated with albumin,    (iii) human recombinant insulin, FGF-1, rosiglitazone, betamethasone, EGF-1, spironolactone, estradiol and vitamin C and/or E.
In a further most preferred embodiment the present invention teaches a composition, preferably for facial treatment, with at least one fat cell growth effector and at least one estrogenic growth factor, comprising biodegradable poly(lactic-co-glycolic acid) (PLGA) microspheres, hexadecanoic acid and/or oleic acid, insulin, FGF-1, rosiglitazone, betamethazone, estradiol and optionally vitamin C and/or E, preferably comprising    (i) PGLA with a molecular weight of 21,000 Da and a ratio of lactic acid and glycolic acid of about 1:1,    (ii) oleic acid and/or hexadecanoic acid, preferably associated with albumin,    (iii) human recombinant insulin, FGF-1, rosiglitazone, betamethasone, estradiol and vitamin C and/or E.
The compositions of the invention are for use in therapeutic or cosmetic treatment, and may optionally comprise further physiologically acceptable excipients and diluents.
Therefore, and in a further aspect, the present invention pertains to the use of a composition of the invention for producing a cosmetic or therapeutic composition, preferably for fat tissue expansion or fat tissue repair.
In a preferred embodiment the composition of the invention is for use in fat tissue expansion, preferably fat tissue volume expansion, more preferably for tissues of the face, the buttocks and/or breasts.
In a more preferred embodiment the composition of the invention is for use in the therapeutic or cosmetic treatment of a condition selected from the group consisting of    (i) medical indications selected from the group consisting of body deformities, preferably post-traumatic scars, breast reconstruction and soft tissue depressions; congenital deformities, preferably pectus excavatum deformity, breast assymetry (e.g. Poland syndrome), hemisyndromes (e.g. CLOVE syndrome, Romberg syndrome); deformities near prostheses, recontouring post-radiation thigh defect, HIV lipodystrophy, mild velopharyngeal insufficiency; and    (ii) non-medical indications selected from the group consisting of cosmetic fat tissue augmentation, preferably fat tissue augmentation of breast, buttock, face, genitals, hands and legs, and iatrogenic deformities, preferably peri-prothetic irregularities, liposuction deformities, and implant deformities.
In a most preferred embodiment the composition of the invention is for use in the therapeutic or cosmetic treatment of a medical indication for post-mastectomy breast reconstruction or for breast or buttock augmentation.
In a further most preferred embodiment the composition of the invention is for use in the therapeutic or cosmetic treatment of a condition selected the group consisting of (I) medical indications selected from the group consisting of facial reconstruction after trauma and deformities, preferably acne scars, HIV induced lipodystrophy, scars; and (II) non-medical indications selected from the group consisting of cosmetic facial augmentation, preferably to cheeks, eyebrows, forehead, glabella, lips, Marionette lines, nasolabial folds, nose, periocular wrinkles and sunken eyelid deformity.
A further aspect of the present invention is directed to a method for the therapeutic or cosmetic treatment of a mammal, preferably a human, more preferably a cosmetic or therapeutic treatment of one of the above-cited cosmetic and therapeutic conditions, comprising the steps of    (i) providing a composition of the invention,    (ii) optionally adminstering anesthesia locally to the tissue to be treated,    (iii) injection administration of the composition and preferably injecting the composition while withdrawing the injection needle,    (iv) optionally repeating step (iii) until the entire tissue is treated.
In the following, the invention will be further illustrated by way of specific embodiments, none of which are to be interpreted as limiting the scope of the claims as appended.